FIG. 8 shows a block diagram for performing what is called a picture-in-picture (hereinafter, referred to as a PinP) in which a slave picture plane is displayed in a conventional master picture plane. In the block diagram shown in FIG. 8, a scaling and a display position of the slave picture plane are set through a field memory 134. Parameters of a writing range (HAct, VAct) and a reading range (HSize, VSize) are supplied to a divider 131. The writing range (HAct, VAct) is a fixed value. In the divider 131, a ratio of magnification or reduction is set. In a horizontal interpolating circuit 132 and a vertical interpolating circuit 133, when the reduction ratio is supplied from the divider 131, an interpolation in the horizontal and vertical directions is performed to an image inputted on the basis of the ratio.
The image supplied from the vertical interpolating circuit 133 is written into the field memory 134 on the basis of a control signal which is supplied from a write memory control circuit 137. A horizontal sync signal, a vertical sync signal, and parameters of a write start position (HPhase, VPhase) and the writing range (HAct, VAct) of a fixed value are supplied to the write memory control circuit 137. Those parameters have a relation shown in FIG. 9. An image surrounded by the writing range (HAct, VAct) of the fixed value is written into the field memory 134.
The written image is read out from the field memory 134 on the basis of a control signal which is supplied from a read memory control circuit 138. The horizontal sync signal, the vertical sync signal, and parameters of a read start position (HPosition, VPosition) and the reading range (HSize, VSize) are supplied to the read memory control circuit 138. Those parameters have a relation shown in FIG. 10. The image written in the field memory 134 is read out so as to be displayed in a range surrounded by the reading range (HSize, VSize).
In a horizontal interpolating circuit 135 and a vertical interpolating circuit 136, when the magnification ratio is supplied from the divider 131, an interpolation in the horizontal and vertical directions is performed to an image supplied on the basis of such a ratio.
It is a feature of PinP that the writing range (HAct, VAct) which is set to the field memory 134 is set to a fixed value on the assumption that the operation to magnify or reduce the whole picture plane is performed. A display picture plane size is determined by only the setting of the reading range (HSize, VSize). FIGS. 9 and 10 show relations between the parameters for the write memory control circuit 137, read memory control circuit 138, and divider 131 and the horizontal and vertical sync signals. As shown in FIG. 9, upon writing, only the write start position (HPhase, VPhase) becomes the parameter. Upon reading shown in FIG. 10, the position and size are set by the parameters of the read start position (HPosition, VPosition) and the reading range (HSize, VSize). An actual display picture plane of PinP is shown in FIG. 11. As shown in FIG. 11, in the conventional PinP, a slave picture plane 142 obtained by reducing an almost whole picture plane of a program on a different channel is displayed in the master picture plane 141.
However, in case of PinP, since almost whole picture plane is reduced and displayed as a slave picture plane, there is a problem such that small characters cannot be discriminated or a small person cannot be recognized. For example, when a relay of a baseball game or a soccer game is displayed on the slave picture plane, a problem such that the score cannot be discriminated occurs.
Further, in case of what is called a picture-and-picture (hereinafter, referred to as a P&P) in which a picture plane 146 is displayed adjacently to a picture plane 145 shown in FIG. 12, when a letter box signal is displayed, there is a problem such that upper and lower black edges are displayed in a frame of the picture plane 146. This is a problem such that the frame which does not correspond to the inherent aspect ratio is displayed in the picture plane.
It is, therefore, an object of the invention to provide a television apparatus in which in a display of PinP or P&P, the portion of an image of an arbitrary size at an arbitrary position in an image of a program on a different channel or an image of another input signal is displayed in the second picture plane, a display method of such a television apparatus, and picture plane control apparatus and method.